Following the advice of Bob Geco, I ordered a product from Meguiar's for the plastic windows. I believe they have two or maybe even three different ones, for progressively more thorough polishing. I am sure if you find a supplier in your area that carries the Meguiar's product line, you will find exactly what you need.
My plastic window was just a little bit foggy. After applying the polish once, rubbing gently, inside and out, the plastic became really like absolutely new, a really big difference. There had been two "rubbing" spots, where it seemed like the plastic was damaged just a little from how the top is folded when down, and these disappeared completely. In other words, I can really recommend this product.
I ordered mine from on a web-store in the US, because they also sold the RaggTopp cleaner and protectant - which is what I was actually looking for to clean and protect the canvas, and I could not find this anywhere in Europe. It cost me a fair amount in import duties. Still, the RaggTopp product is excellent, the top turned out very clean and water now beads and runs off, rather than being soaked into the material.
white 1969 280 SL